1. Field of the Invention
This invention relates generally to guides for cutting tools, and more particularly to a saw guide for accurately and efficiently cutting a sheet material to a particular dimension.
2. Description of the Background Art
Sheet material is commonly used to cover large areas of a structure at construction sites. Typical sheet materials include plywood, particleboard, oriented strand board (OSB), wallboard, and varieties of laminates. Plywood and OSB are typically used to form the outside walls, the roof, and the floors of a structure. Similarly, wallboard (e.g., drywall, paneling, etc.) is secured to the interior frame of the structure to define and cover inside walls. Finally, laminates provide decorative coverings for flat surfaces (e.g., floors, counters, etc.). Installation of the sheet materials generally requires a construction worker to make at least one large cut to size the sheet material appropriately for the application.
Preparing the sheet material for proper installation is a time consuming process. Sheet material is typically prepared at a cutting station centrally located at the construction site, and is cut with a handheld circular saw via the following process. First, the worker measures a predetermined distance from an end edge of the sheet material using a tape measure, and marks a “crows foot” reference mark on the sheet material near one side edge of the material. The worker then repeats the measuring and marking procedure to provide a second reference mark near the opposite side edge of the material. Next, the worker stretched a chalk line across the two reference marks, and snaps the chalk line to mark a cut line on the material parallel to the end edge of the sheet at the predetermined distance. The worker then cuts the sheet material along the chalk line to yield a piece of material the desired size. The several steps required to cut each piece of sheet material are time consuming, and result in high labor cost, even for experienced workers, to properly cut the sheet material.
Many prior art devices have attempted to make it easier to cut sheet material more accurately and efficiently. For example, frame guides attach to the sheet of material and either attach to or abut the hand saw, to ensure that the cut is straight. Typically, frame guides are bulky and sometimes completely stationary, thereby requiring additional labor time to manipulate the cutting tool and/or sheet material into the proper position to make accurate cuts. Further, frame guides do not eliminate the need to mark the cut location on the sheet of material.
Another type of guide, commonly known as a rip fence, engages a reference edge of the material and attaches to the saw to maintain the saw at a set distance from the reference edge during the cut. Rip fences can be difficult to manipulate and use, because the guide must be as long as the cut distance. Further, the edge of a rip fence hangs over the reference edge of the sheet material, and at long cut distances it is difficult for the user to slide the rip fence along the edge of the material in unison with the motion of the saw.
Yet another problem with known cutting guides is that it is difficult to make fine corrections in the cutting path during a cut. For example, a slight deviation between the angle of the saw blade and the straight edge of the guide can result in the side of the blade binding against the sheet material, or pushing the rip guide away from the reference edge of the sheet material. In particular, if the blade of a saw is not aligned exactly with the cut path defined by the blade, the saw will want to follow a slightly different (either toward or away from the guide) cut path. Because the path of the saw is fixed by the guide, the operator will not be able to correct for this problem.
What is needed, therefore, is a guide for a cutting tool that facilitates quick and accurate positioning of a blade of the cutting tool at any desired distance from a reference edge of a piece of sheet material. What is also needed is a guide that need not be as long as the cut that is being made. What is also needed is a guide that facilitates user correction of a cut path during a cut.